Department of Radiology
Imaging Division
University Hopital Zürich

Within the last years, many different MRI techniques for functional assessment of the kidneys have been developed: e.g. Arterial Spin Labeling (ASL), Blood Oxygenation Level Dependant (BOLD) imaging, and Diffusion Weighted Imaging (DWI). One of the most interesting techniques is the assessment of renal contrast-media uptake and excretion. The gadolinium-based contrast-agents (such as Gd-DTPA) are freely filtered into the Bowman's capsule. Using an optimized MR imaging techniques, the side different renal function can be calculated from the signal increase in the parenchymal phase (2-3 min) after bolus injection of gadolinium-based contrast-media. Moreover, the signal change as a function of progressing contrast-media excretion measured in the renal pelvis allows the assessment of a compensated or non-compensated obstruction of the urinary drainage. To obtain meaningful signal curves, the imaging technique has to be optimized regarding the dependance of signal linearity and tissue gadolinium concentration; moreover breathing motion has to be compensated.

In the clinical routine, the renal function is measured in terms of the glomerular filtration rate (GFR). The gold standard for the assessment of the GFR is the inulin clearance at steady state; however, this approach is cumbersome and time consuming. Similar to the whole-body tracer clearance in scintigraphy, functional MRI with the use of gadolinium-based contrast media allows the quantification of the GFR using an approach based on the renal clearance of gadobutrol from the extracellular fluid volume monitored via time-signal curves measured in liver parenchyma. Therefore, contrast-enhanced dynamic MR nephrography may provide the comprehensive evaluation of renal function and vessel morphology within a single examination. This technique seems especially versatile for evaluation of potential kidney donors within a one-stop-shop exaimnation. The MR-based calculation of split renal function and potential urinary drainage obstruction is especially suitable in the evaluation of pediatric patients with urinary tract anomalies.

Selected contributionsu>
Artunc F, Rossi C, Boss A. MRI to assess renal structure and function. Curr Opin Nephrol Hypertens. 2011; 20: 669-675.

Artunc F, Yildiz S, Boss A, Frenzel T, Schlemmer HP, Schick F, Risler T, Häring HU, Rossi C. Measurement of glomerular filtration rate using dynamic magnetic resonance imaging in patients with chronic kidney disease. J Nephrol. 2011; 24: 482-489.

Artunc F, Yildiz S, Rossi C, Boss A, Dittmann H, Schlemmer HP, Risler T, Heyne N. Simultaneous evaluation of renal morphology and function in live kidney donors using dynamic magnetic resonance imaging. Nephrol Dial Transplant. 2010; 25: 1986-1991.

Rossi C, Boss A, Artunc F, Yildiz S, Martirosian P, Dittmann H, Claussen CD, Heyne N, Schick F, Schlemmer HP. Comprehensive assessment of renal function and vessel morphology in potential living kidney donors: an MRI-based approach. Invest Radiol. 2009; 44: 705-711. Boss A, Schaefer JF, Martirosian P, Obermayr F, Fuchs J, Claussen CD, Schick F, Schlemmer HP. Dynamic magnetic resonance nephrography and urography of uropathies in children. Rofo. 2007; 179: 832-840.

Boss A, Martirosian P, Schaefer JF, Gehrmann M, Artunc F, Risler T, Oesingmann N, Claussen CD, Schlemmer HP, Schick F. Dynamic magnetic resonance nephrography: is saturation recovery TrueFISP advantageous over saturation recovery TurboFLASH? Invest Radiol. 2007; 42: 256-262.

Boss A, Martirosian P, Gehrmann M, Artunc F, Risler T, Oesingmann N, Claussen CD, Schick F, Küper K, Schlemmer HP. Quantitative assessment of glomerular filtration rate with MR gadolinium slope clearance measurements: a phase I trial. Radiology. 2007; 242: 783-790.

Boss A, Schaefer JF, Martirosian P, Hacker HW, Darge K, Claussen CD, Küper K, Schick F, Schlemmer HP. Contrast-enhanced dynamic MR nephrography using the TurboFLASH navigator-gating technique in children. Eur Radiol. 2006 ; 16:1509-1518.

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Andreas Boss
Department of Radiology
Imaging Division
University Hospital of Zürich
Rämistr. 100
8006 Zürich
Switzerland
Tel.: +41-44-2553677
FAX: +41-44-2554344
Email: andreas.boss@usz.ch